You're wasting your time with the agency, that I can tell you. I so hate it when agencies make you feel like you're third class because you're not a size 10 or 12.
I also had a young Black woman email and tell me that the agency she wanted to sign up to told her that there wasn't a market for Black escorts and she was about to give up. Which is the biggest load of bollocks I've ever heard. The problem with working for an agency is that they have their "quotas" of what/who they should have on their books. If they already have one 14/16 on their books, they're not going to sign anymore up. Same goes for escorts of any ethnicity. They don't want to take on any more because they don't know what to do with them.
I'm Black and a size 22 and I was with an agency when I first started and I got maybe two clients in two months. Imho agencies don't know how to market BBW and ethnic working girls, unless it's something they specialise in. It didn't take me long to realise that I would be better off as an independent. So that's what I did. I knew how to market myself and what my best selling points were, and with the help of another fabulous escort, I got on with it. And in over six years and a half years I haven't looked back.
And as for the no trousers policy, what the hell.....? I wear mainly trousers on my bookings, especially in the winter, and I've never had a customer complain about my state of dress. I also wear fashionable flat shoes because I'm tall and I don't like heels, and when you're travelling around in London and on the Underground you want to be as comfortable as possible and not turn up to the booking in a state. I even wore a pair of jeans once because I was coming from somewhere else first. I let the customer know ahead of time and he was happy with that. He said it wasn't the packaging, it was what was underneath that counted. Smart guy.
If you want to work for an agency, find one that caters to BBWs. There's Curves Unlimited http://www.curvesunlimited.com/ They're actually found on this site http://www.prettybigescorts.com/ which only features indies over the size of 14. I've been on there more or less since its inception and it's where I get most of my work.
If starting out as an independent might be an option then just follow this quick 10 point guide http://www.saafe.info/10point.htm and when you have some more time, read the rest of Saafe. And if you have any more queries, please feel free to ask on here.